The invention discloses a power grid reactive compensation optimization configuration system and method based on a multi-knapsack problem solution. The power grid reactive compensation optimization configuration method comprises steps of establishing an optimization model in which the total value of articles inside the knapsack is up to a target function through abstracting a transformer station having reactive vacancy as an article and viewing a transformer station having reactive opulence as a knapsack, adopting a heredity algorithm to solve a reactive balance relation of the full power grid, and stipulating a reactive compensation increase scheme according to a nearby arrangement principle. The analysis for the whole process is automatically finished through a data input module, a reactive vacancy calculation module, a reactive balance analysis module, a compensation increase distribution analysis module and a data output module, and does not need to be intervened by people. The power grid reactive compensation optimization configuration system and method improve the efficiency of power grid reactive planning, improve the reactive voltage optimization operation level of the power grid, and have a good application prospect.